This is a stupid question I know but I've gotta ask because I'm working another problem...Does fluid flow from the trans through the lines to the radiator/cooler when ever the truck is running, in other words, all the time??

My temp gauge doesn't work (yes, it's mechanical and installed in the line) and I want to rule out all possibilities before I let Autometer have it. Just wanted to make sure there's no valve or something that may sometime stop the flow of fluid to the radiator/cooler that I've never heard of before.

 

that the fluid flows at maximum when the tourge convertor locks up

 

That may be true, but I am looking for reassurance that fluid is flowing through these lines always, anytime the engine is running...

 

I would say yes there is flow all the time. Crack a cooling line loose while the engine is running and you'll see for sure. Sounds like a f/u gauge.

As a side note I put the Cyberdyne red(Green available) digital tranny temp on mine. Starts reading @70* which will work for me in cooler weather. Takes a half hour to come up to temp. Runs about 70* over ambient running around town.

 

Fluid should flow to the cooler at all times. In some cases of extreme pressure demand in the transmission flow to the cooler can be stopped for a couple seconds, but that's rare.

Flow is reduced when the torque converter is locked, not when it's open. When the torque converter is locked the transmission's cooling requirements are much less, so the flow is reduced to the cooler.

 

Thanks guys. Yes it is a f/u gauge but I wanted to double check myself...the second one at that. Getting ready to be a third next week. The needle sticks around 125 or so and doesn't move until it get's ready to. I drive for 20+ miles in 100* weather (all driving conditions) so I know the fluid is warm but the needle just sits there. Eventually it will come unstuck and work after that, until the next time it sits all day. Two gagues in a row have done this. I am sending the second one back this week for a third gauge because of identical problems.

 

With my digital tranny gauge I'm not completely happy with that either. The display is bright even during the day and is way too bright at night even when dimmed.

Gotta call Cyberdyne to find out if there is a resistor or something I can throw inline to dim it a bit more.

Think maybe a ferrite core from Clarion will work?

With a stone cold engine the digital reads the same as the overhead console so I guess it's calibrated close enough.

 

Mark, I think that is almost right. My understandning of the coolant bypass valve on the 4R100 (does a 4R70 even have one?) is that until the fluid gets to X temp, the fluid is diverted from the converter out port directly to the rear lube in, so for a few miuntes or more, the fluid would not be flowing to the radiator.
By the way, saw your name on some paperwork today, didn't now you had changed over to the new tranny.

G

 

Do you guys know of another place to install the temp probe on a mechanical temp gauge (in a 4R70) besides tapping into the cooling lines? I have heard of other places with electrical gauges but don't know where it's at or if that big temp bulb will fit. No, I don't have a way to put it in the pan.

 

There is a small pipe plug near the top of the trans on the drivers side. It is marked with a "line" or "test". Forget which. That's where I put my electrical sender.

It is a small port so I would think a mechanical sender probe would require a few fittings to make it work.

My electrical sender was the same thread so it screwed right in.

 

The 4R70W does not have a bypass. There is always fluid flowing.

Even with the bypass the 4R100 will flow a small amount of fluid to the cooler.

Yes, I'm now a TorqShifter!

 

Welcome to "the Big Box". Funny thing is, when 4R100 phases out of 2 shifts, I think I'm gonna end up working on 4R70W and 5R55S Line, go figure. They're only taking 8 repairman on the Torqueshift line and I may not make it, they opened the new jobs up to everyone in the zone being RIFed, so I'll have to learn new tranny, but it won't be the one I wanted. Oh well.



G